jim henley has more on the chaos and the confusion from the scene today. >> dozens of victims, bags abandoned in that chaos. blocked roadways and of course, the huge crowds. posted online, can you hear the tense moments after the explosions, as first respenders tried to get all units to the scene around the finish line. >> i want one road cleared, ambulances in and out. i need lanes open here. >> boylston, we need to set up a perimeter. get people away. >> get everybody out there. use kagz, there may be additional devices. use caution. >> i need someone on social media, let people know. we are sweeping the street to make sure it is safe. get them out once it is swept. we have all the victims off the scene. >> we are finishing the evacuation of the surrounding buildings. >> the last call, referring to an explosive sweep that lasted hours this evening n midst of everything, you hear for a call at the jfk library, that turned out to be an unrelated fire. many in the marathon crowd that tried to call out on their cell phones couldn't, because the system was overloaded. much like the trouble we ha